Thallium-201 gated single-photon emission tomography for the assessment ofleft ventricular ejection fraction and regional wall motion abnormalities in comparison with two-dimensional echocardiography

Simultaneous assessment of myocardial perfusion and function by gated singl e-photon emission tomography (GS) after a single tracer injection provides incremental information and is feasible with technetium 99m sestamibi. The present study validated the use of GS with thallium-201 for the assessment of left ventricular ejection fraction (LVEF) and regional wall motion by co mparison with two-dimensional (2D) echocardiography (echo), which has not b een done before. After injection of 111 MBq Tl-201 at peak bicycle exercise (n=55) or pharmacological stress (n=17), GS was acquired 15 (post stress) and 120 min post injection (rest) on a double-head camera. An automatic alg orithm (QGS) was used for processing. Echo (Acuson Sequoia C256) was per fo rmed immediately after rest GS. LVEFs assessed by GS and echo were correlat ed. The overall and segmental sensitivity and specificity of GS for the det ection of regional wall motion abnormalities (WMAs) were calculated, echo s erving as the gold standard. Perfusion abnormalities were scored. The succe ss rate of the automatic algorithm was 100%, and visually assessed image qu ality was good to excellent in 88% of cases. Poststress and pest LVEF as as sessed by GS were highly correlated (r=0.91). Good correlations were obtain ed between post-stress LVEF (GS) and rest LVEF (echo) and between rest LVEF (GS) and rest LVEF (echo) (r=0.76 and 0.86 respectively). In patients with a reduced LVEF of less than 50% (n=23), these correlations were even bette r (r=0.84 and 0.89 respectively). Regional wall motion abnormalities (WMAs) were identified by GS with high sensitivity and specificity (88%-100% and 82%-98% respectively) and were directly related to the extent and severity of stress as well as of resting perfusion defects, it is concluded that GS with Tl-201 is a feasible and reliable tool for the evaluation of patients with compromised left ventricular function in the context of coronary arter y disease, and thus improves diagnosis and prognostic stratification. Regio nal WMAs were identified with high diagnostic accuracy and the method may p rove helpful for the detection of myocardial viability.